Homework Help:
Magnetic materials

today, my teacher asked us a question. he asked, have you ever wondered why materials are magnetic? why are some materials magnetic and some are not? are the magnetic materials specifically chosen to be magnetic or non magnetic? what makes them magnetic?

and my class was silent, no one knew how to answer that simple yet seemingly complicated question.

Your teacher asked a rather profound question. I certainly am not going to be able to answer it much here. An intermediate physics student, who has studied magnetostatics might be able to scratch the surface by studying angular momentum of charged particles, and then roughly applying that to the behavior of electrons within the atoms of a given material (and "roughly" is an understatement). But any deeper than that and it can get very advanced, very quickly.

A very famous physicist, Richard Feynman, had these general words to say on the subject:

There are three types of magnetic materials, diamagnetic, paramagnetic and ferromagnetic. Diamagnetic acts against a magnetic field, while paramagnetic supports magnetic field and ferromagnetic strengthen magnetic field. Basically these properties are due to the arrangement of particles. For instance, paramagnetic materials generate magnetic moments that make the field stronger and ferromagnetic materials have magnetic domains that arrange in the same pattern as that of magnetic field. I think you should search for these.